EP2596288B1

EP2596288B1 - Desuperheaters having vortex suppression

Info

Publication number: EP2596288B1
Application number: EP11728487.7A
Authority: EP
Inventors: Theodore Paul Geelhart; John Graham Brett; Justin Paul Goodwin; Jesse Creighton Doyle
Original assignee: Fisher Controls International LLC
Current assignee: Fisher Controls International LLC
Priority date: 2010-07-20
Filing date: 2011-06-17
Publication date: 2016-05-11
Anticipated expiration: 2031-06-17
Also published as: JP2014504352A; CA2808041A1; AU2011280120A1; EP2596288A2; WO2012012062A3; BR112013001340A2; JP5956990B2; WO2012012062A2; CN103547859A; NO340588B1; CN103547859B; NO20130111A1; US20120017852A1; AR084470A1; MX340864B; RU2584102C2; MX2013000843A; RU2013106758A; CA2808041C

Description

FIELD OF THE DISCLOSURE

The present disclosure relates generally to desuperheaters and, more particularly, to desuperheaters having vortex suppression.

BACKGROUND

Steam supply systems typically produce or generate superheated steam having relatively high temperatures (e.g., temperatures greater than the saturation
temperatures) greater than maximum allowable operating temperatures of downstream equipment. In some instances, superheated steam having a temperature greater than the maximum allowable operating temperature of the downstream equipment may damage the downstream equipment.
Thus, a steam supply system typically employs a desuperheater to reduce or control the temperature of the fluid or steam downstream from the desuperheater. Some known desuperheaters (e.g., insertion- style desuperheaters) include a body portion that is suspended or disposed substantially perpendicular to a fluid flow path of the steam flowing in a passageway (e.g., a pipeline). The desuperheater includes a passageway that injects or sprays cooling water into the steam flow to reduce the temperature of the steam flowing downstream from the desuperheater.
JP 2000 291907 A discloses a spray nozzle. The spray nozzle is situated upstream from an overheat reducer and forms a protrusion part on a surface by winding a coil-form member around its outer periphery. In a special embodiment, a small-scale steam vortex is generated in a position situated downstream from a spray nozzle to enhancing a turbulent property and to flattening a flow velocity fluctuation spectrum. In US 4 442 047 A a multi-nozzle spray desuperheater is disclosed. The steam desuperheater comprises a liquid spray tube assembly which is positioned in a steam line and includes a plurality of liquid outlet nozzles, and a hollow piston plug axially movable therein upwardly from a lower valve seat to progressively open the outlet openings. The desuperheater comprises further a cage structure, including an internal flow path. The desuperheater comprises a head assembly and a spray tube assembly. The head assembly includes an integral mounting flange for mounting the desuperheater to a flange of a desuperheater supporting structure secured to a main steamline.
However, in some applications, superheated steam flows at relatively high velocity through the fluid flow path and may undergo an unsteady flow across the body of the desuperheater interposed in the fluid flow path. Such high velocity or unsteady flow may cause vortex shedding, resulting in vortex induce vibrations and/or lift forces that are imparted on the body of the desuperheater and which may cause the body to vibrate. In particular, in some instances, vortex induced vibrations that resonate at frequencies that are substantially similar or identical to a natural frequency of the body of the desuperheater may cause the desuperheater to fracture or otherwise become damaged, thereby reducing the operating life of the desuperheater.

SUMMARY

The invention is defined by appended independent claim 1
In one example, an example desuperheater includes a body portion having a passageway to provide cooling water to a fluid flow path a vortex suppression device adjacent an end of the body. The vortex suppression device is disposed within the fluid flow path to attenuate or suppress vortex shedding or flow induced vibrations imparted on the desuperheater by a fluid in the fluid flow path.
In another example, an example a desuperheater includes a body having a passageway between a flange at a first end of the body and at least one opening at a recessed portion and adjacent a second end of the body. The body is suspended within the fluid flow path when the desuperheater is coupled to a fluid flow path via the flange such that the body is substantially perpendicular to a fluid flow and at least one opening is substantially parallel to the fluid flow. The desuperheater includes a vortex suppression device integrally formed with the body adjacent the second end and the recessed portion that is to attenuate or suppress vortex shedding or vortex induced vibrations imparted on the body of the desuperheater by a fluid flowing across the body.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a fluid system implemented with a known desuperheater apparatus.
FIG. 2A illustrates a fluid system implemented with an example desuperheater having vortex suppression described herein.
FIG. 2B illustrates the example desuperheater of FIG. 2A.
FIG. 3 illustrates another example desuperheater described herein.
FIG. 4 illustrates yet another example desuperheater described herein.

DETAILED DESCRIPTION

The example desuperheater apparatus described herein provide vortex suppression to significantly reduce or eliminate vortex induced vibrations produced by vortex shedding, thereby increasing the operating life of the desuperheater. An example desuperheater described herein may be utilized with a steam supply system to significantly reduce vortex induced vibrations that may be caused by superheated steam flowing at a relatively high velocity (e.g., 91 m/s (300 feet/second)) across the desuperheater.
In particular, an example desuperheater described herein includes a vortex suppression apparatus adjacent an end of a body of the desuperheater. The vortex suppression apparatus suppresses or significantly reduces vortex shedding to alter or attenuate a resonant vortex induced vibration and associated magnification of the steady drag and/or disrupt or prevent formation of a vortex street (e.g., a two-dimensional vortex street or wake).
In some examples, a vortex suppression apparatus is integrally formed with the body of the desuperheater. In these examples, the vortex suppression apparatus may include a helical strake, a plurality of ribs, splines, a plurality of protruding surfaces (e.g., curved surfaces), a plurality of apertures and/or any other suitable geometry or shape to suppress or significantly reduce vortex shedding that may otherwise develop as fluid flows across the body of the desuperheater. The desuperheater and/or the vortex suppression apparatus may be made of metal (e.g., stainless steel) and the vortex suppression apparatus may be formed with, or coupled to, a body of the desuperheater via, for example, machining, welding, casting and/or any other suitable manufacturing process(es).
FIG. 1 illustrates an example fluid supply system 100 (e.g., a steam supply system) implemented with a known desuperheater 102. As shown, the desuperheater 102 is coupled to a pipeline 104 via flanges 106 and 108 between a first side or inlet 110 and a second side or outlet 112 of the pipeline 104. A superheated fluid (e.g., steam, ammonia, etc.) flows at a relatively high velocity between the inlet 110 and the outlet 112 across a body 114 of the desuperheater 102.
As shown, the body 114 includes a fluid passageway 116 between a first end 118 and a second end 120. In this example, the body 114 is a cylindrically-shaped body (e.g., a bluff body). The first end 118 includes a flange portion 122 that is disposed between the flanges 106 and 108 to couple the desuperheater 102 to the pipeline 104. As shown, when coupled to the pipeline 104, the body 114 is suspended within a fluid flow path 124 substantially perpendicular to the direction of the superheated fluid flowing through the fluid flow path 124. In other words, the second end 120 of the body 114 is not secured or otherwise coupled to the pipeline 104 and may flex, bend and/or move relative to a longitudinal axis 126 during operation.
In operation, the superheated fluid flows across the body 114 of the desuperheater 102 at a relatively high velocity between the inlet 110 and the outlet 112 at a superheated temperature (e.g., a temperature above the saturation temperature of the fluid). The desuperheater 102 injects or sprays cooling water into the fluid flow path 124 via the passageway 116 and openings 128 to cool or reduce the temperature of the superheated fluid at the outlet 112 (e.g., to about the saturation temperature of the superheated fluid). Such cooling may be required to prevent damage to equipment downstream from the outlet 112.
However, because the body 114 is disposed in the fluid flow path 124 the velocity and/or the pressure of the superheated fluid may vary or fluctuate over a portion of the body 114. Such variation or fluctuations of pressure and/or velocity may cause a turbulent or unsteady flow (e.g., a fluid flow having a relatively high Reynolds number) to develop as the superheated fluid flows across the body 114 of the desuperheater 102. In severe applications in which the superheated fluid has a relatively high velocity, unsteady flow can generate separated or detached flow over a substantial portion of the body 114, which can cause vortex shedding.
Vortex shedding may produce a fluid flow field having a vortex street (e.g., a two-dimensional vortex street or wake) downstream from the body 114 that induces or causes fluctuating pressures or vibrations (e.g., a eddy flow) to be imparted on the body 114. As the velocity of the superheated fluid flow increases, vortices are alternately shed (e.g., asymmetrically) on each side of the body 114 substantially perpendicular to the fluid flow. Additionally, asymmetrical vortex shedding often develops or creates an oscillating flow characteristic having a discrete or shedding frequency that can cause the body 114 to oscillate or vibrate during operation.
These vortices or oscillating fluid flows can create harmful periodic forces or vibrations that are imparted on the body 114 of the desuperheater 102. For example, such forces can cause excessive vibrations and/or lift forces to be imparted against the body 114. In some instances, a shedding frequency of vortices that is substantially similar or identical to a natural frequency of the body 114 of the desuperheater 102 creates a resonant vibration that causes the body 114 to vibrate or oscillate in a violent manner, causing the body 114 to break, fracture and/or otherwise become damaged.
FIG. 2A illustrates an example fluid flow system 200 implemented with an example desuperheater 202 described herein. FIG. 2B illustrates the example desuperheater 202 of FIG. 2A. Unlike the desuperheater 102 of FIG. 1, the desuperheater 202 includes a vortex suppression apparatus or device 204 to suppress or significantly reduce vortex shedding and, thus, reduce vortex induced vibrations that may be caused by a fluid (e.g., superheated steam, superheated ammonia, etc.) flowing across the desuperheater 202 at a relatively high velocity (e.g., 107 m/s (350 feet/second)).
In this example, the desuperheater 202 is coupled to a fluid pipeline 206 that provides a fluid flow path or passageway 208. For example, the fluid flow system 200 may be a heat recovery system generator, a boiler interstage attemperation system, or any other fluid system. As shown, the desuperheater 202 is disposed between an inlet or first side 210a of the pipeline 206 and an outlet or second side 210b of the pipeline 206. The inlet 210a may be fluidly coupled to a first steam source (e.g., a superheater, an exit of a steam turbine) and the outlet 210b may be fluidly coupled to downstream equipment such as, for example, a steam turbine. The example desuperheater 202 may be utilized in severe service applications in which the desuperheater 202 may be exposed to high thermal cycling and stress, high fluid flow velocities, and/or fluid or vortex induced vibrations.
Referring to FIGS. 2A and 2B, the desuperheater 202 includes a body 212 having a channel or passageway 214 between a first end 216 of the body 212 and at least one opening 218a disposed in a recessed or flat portion 220 and adjacent a second end 222 of the body 212. As shown, the body 212 is a generally elongated cylindrical body and includes the opening 218a and another opening 218b. The body 212 and the passageway 214 are substantially parallel to an axis 226 (i.e., substantially perpendicular to the fluid flow) and each of the openings 218a,b has an axis 228 that is substantially perpendicular to the axis 226 (i.e., substantially parallel to the fluid flow). Additionally, the openings 218a,b may each receive a nozzle (not shown) that may be configured to spray cooling fluid (e.g. water) into the fluid being cooled (e.g. steam). Additionally or alternatively, although not shown, the body 212 may include a tapered profile between the first end 216 and the second end 222.
The first end 216 of the body 212 includes a flange 230 to couple the desuperheater 202 to the pipeline 206. The flange 230 may be welded to the body 212 or may be integrally formed with the body 212 via, for example, casting, machining or any other suitable manufacturing process(es). Also, as shown, a mounting flange 232 is integrally formed with the flange 230 and/or the body 212 to couple the desuperheater 202 to the pipeline 206 via a flange 234 of the pipeline 206. Fasteners 236 couple the mounting flange 232 and the flange 234 of the pipeline 206. However, in other examples, the mounting flange 232 may be a separate piece and the flange 230 of the body 212 may disposed or mounted between the flange 232 and a flange 234 of the pipeline 206. The mounting flange 232 may include a gasket and/or a recess (not shown) to receive the flange 230 of the body 212. When coupled to the pipeline 206, the body 212 is suspended within the fluid flow path 208 and may flex or move (e.g., move slightly or vibrate) relative to the longitudinal axis 226 during operation. In other words, the second end 222 of the body 212 is not coupled or secured to the pipeline 206. The desuperheater 202 is an insertion type desuperheater that is inserted or disposed within the fluid flow path 208 substantially perpendicular to the fluid flow.
A control valve 238 (e.g., a sliding stem valve) is fluidly coupled to an inlet 240 of the passageway 214 of the body 212 to control the flow of a cooling fluid to the passageway 214. The valve mounting flange 244 is coupled to the mounting flange 232 via, for example, welding.
As shown in FIGS. 2A and 2B, the vortex suppression device 204 is integrally formed with the body 212 (e.g., via machining) adjacent the second end 222 and the recessed portion 220. For example, the vortex suppression device 204 may be integrally formed with the body 212 by machining a bar stock or block of metal (e.g., stainless steel). In other examples, the vortex suppression device 204 may be formed with, or coupled to, the body 212 via casting, welding or any other suitable manufacturing process(es). For example, the vortex suppression device 204 may be coupled to the body 212 via welding or any other suitable fastening mechanism(s).
The body and/or the vortex suppression device 204 may be composed of carbon steel (e.g., ASTM SA105, ASTM WCC, etc.), alloy steel (e.g., ASTM F91, ASTM C12A, etc.), stainless steel (e.g., stainless steel 316) and/or any other suitable material(s). Although in this example the vortex suppression device 204 is composed of the same material as the body 212, in other examples, the vortex suppression device 204 and the body 212 may be composed of different materials.
The vortex suppression device 204 of FIGS. 2A and 2B includes a plurality of helical strakes. As shown in this example, the vortex suppression device 204 includes helical strakes 246a-c (or corkscrew configuration) composed of, for example, carbon steel or stainless steel. The helical strakes 246a-c are disposed along a portion of the body 212 adjacent the second end 222 and wind in a non-continuous configuration about an outer surface 248 of the body 212 (e.g., interrupted or cut-off by the recessed portion 220). However, in other examples not forming part of the invention, the helical strakes 246a-c may wind in a continuous manner about the outer surface 248 of the body212 and/or the recessed portion 220. For example, a helical strake may be disposed on the outer surface 248 of the body 212 and/or the recessed portion 220 between the openings 218a,b. The vortex suppression device 204 may include any number of helical strakes having any thickness or size and may project any distance from the outer surface 248 of the body 212 to provide a non-linear or substantially non-smooth outer surface 248 to suppress or significantly reduce vortex shedding and, thus, disrupt or prevent the formation of vortex induced vibrations or oscillations as the fluid flows across the body 212 during operation.
For example, the number of helical strakes may be determined by a factor or ratio of an outer diameter of the body 212. As shown, the vortex suppression device 204 includes the three helical strakes 246a-c that are generally parallel relative to each other. The pitch of the helical strakes 246a-c may be, for example, between about 3.5 to 5 times the outer diameter of the body 212 and the height may be, for example, approximately 0.1 times the outer diameter of the body 212. In other examples, the helical strake 246a may have a different pitch and/or height than the helical strakes 246b and/or 246c. The helical strakes 246a-c may be integrally formed with the body 212 via machining or the helical strakes 246a-c may be separate parts that are welded to the body 212. In other examples, as shown in FIGS. 3 and 4, the vortex suppression device 204 may include any other suitable shape or surface to suppress or reduce vortex shedding and, thus, vortex induced vibrations or oscillations imparted on the body 212.
In operation, a superheated fluid (e.g., superheated steam, superheated ammonia, etc.) flows across the desuperheater 202 at a relatively high velocity (e.g., 107 m/s (350 feet/second)) and a relatively high temperature (e.g., a temperature range of about 593°C and 704°C (1100°F and 1300°F)) between the inlet 210a and the outlet 210b of the pipeline 206. As the superheated fluid flows across the body 212 of the desuperheater 202 between the inlet 210a and the outlet 210b, the desuperheater 202 injects or sprays a cooling fluid (e.g., water) into the superheated fluid flowing across the desuperheater 202 to reduce or control the temperature of the superheated fluid at the outlet 210b to approximately, for example, the saturation temperature of the superheated fluid. In particular, the desuperheater 202 injects or sprays atomized droplets of the cooling fluid (e.g., cooling water) into the fluid flow path 208 via the passageway 214 and the openings 218a,b. The cooling fluid evaporates, drawing energy from the superheated fluid to reduce the temperature of the superheated fluid to, for example, near the saturation temperature of the superheated fluid (e.g., the saturated temperature of steam).
The rate of cooling may be controlled by the droplet size, the droplet distribution, and/or the velocity of the cooling fluid and the temperature of the superheated fluid (e.g., the steam) in the fluid flow path 208 may be controlled by varying the flow rate of the cooling fluid via the control valve 238. Further, the control valve 238 may include a controller to receive a signal from a downstream sensor that indicates the temperature of the superheated fluid flowing at the outlet 210b of the pipeline 206. Based on the temperature sensed by the sensor, the control valve 238 moves an actuator of the control valve to modulate or control the flow rate of the cooling fluid flowing into the fluid flow path 208 via the passageway 214 and the openings 218a,b to control the temperature of the superheated fluid at the outlet 210b. As noted above, such cooling of the superheated fluid may be required to prevent damage to equipment (e.g., a steam turbine) downstream from the outlet 210b.
As the fluid flows across the body 212 of the desuperheater 202 at relatively high velocity, the vortex suppression device 204 suppresses or significantly reduces vortex shedding to disrupt an unsteady flow that may otherwise develop as the superheated fluid flows across the body 212 of the desuperheater 202. As noted above, an unsteady flow (e.g., a fluid flow having a relatively high Reynolds number) may cause vortex shedding resulting in the formation of a fluid flow field having a vortex street downstream from the body 212. Such a vortex street may create an oscillating flow or vortex induced vibrations, which may cause harmful periodic forces to be imparted on the body 212 of the desuperheater 202.
However, the vortex suppression device 204 disrupts or reduces vortex shedding to prevent or attenuate formation of a vortex street downstream from the body 212 of the desuperheater 202. As a result, the vortex suppression device 204 reduces vortex induced vibrations or oscillating flows that may otherwise be imparted on the body 212 of the desuperheater 202. As the superheated fluid flows across the body 212, the vortex suppression device 204 significantly reduces or prevents vortices from alternating or asymmetrically shedding or forming on either side of the body 212 substantially perpendicular to the fluid flow path. In other words, the vortex suppression device 204 promotes boundary layer detachment or separation relative to the body 212 as the superheated fluid flows across the body 212.
More specifically, the vortex suppression device 204 or the helical strakes 246a-c reduce or change the frequency of the vortices shedding in the fluid flow to mitigate flow or vortex induced vibration effects and associated lift forces on the body 212 of the desuperheater 202. In this manner, the vortex suppression device 204 or the helical strakes 246a-c impede development of a resonance condition between a shedding frequency or oscillation of the vortices that is substantially similar or identical to a natural frequency or oscillation of the body 212 of the desuperheater 202. As a result, the desuperheater 202 prevents a resonant condition or resonant vibration between the shedding frequency of the vortices and the natural frequency of the body that can cause the body 212 to break, fracture, crack, and/or otherwise become damaged, thereby increasing the operating life of the desuperheater 202.
FIG. 3 illustrates another example desuperheater 300 that may be used to implement the example system 200 of FIGS. 2A and 2B. The desuperheater 300 is includes another example vortex suppression apparatus or device 302 to attenuate or reduce vortex shedding and/or vortex induced vibration. Those components of the example desuperheater 300 of FIG. 3 that are substantially similar or identical to those components of the example desuperheater 202 described above in FIGS. 2A and 2B and that have functions substantially similar or identical to the functions of those components will be referenced with the same reference numbers as those components described in connection with FIGS. 2A and 2B and will not be described in detail again below. Instead, the interested reader is referred to the above corresponding descriptions in connection with FIGS. 2A and 2B.
The vortex suppression apparatus or device 302 is disposed along a body 212 adjacent the second end 222 and the recessed portion 220. In this example, the vortex suppression device 302 includes a plurality of ribs or splines 304 disposed adjacent the second end 222 of the body 212. For example, the plurality of ribs or splines 304 may form or define a splined end. The plurality of ribs or splines 304 may be continuously disposed about an outer surface 306 of the body 212 spaced apart in either equal or random, varying distances. In other examples, the plurality of ribs 304 may be angled or inclined relative to the axis 226 of the body 212 or wind (e.g., helically wind) around the outer surface 306 of the body 212. The plurality of ribs or splines 304 may be formed via machining or any other suitable manufacturing process(es).
FIG. 4 illustrates another example desuperheater 400 that may be used to implement the example system 200 of FIGS. 2A and 2B. The desuperheater 400 includes another example vortex suppression apparatus or device 402 to attenuate or reduce vortex shedding and/or vortex induced vibration. Those components of the example desuperheater 400 of FIG. 4 that are substantially similar or identical to those components of the example desuperheater 202 described above in FIGS. 2A and 2B and that have functions substantially similar or identical to the functions of those components will be referenced with the same reference numbers as those components described in connection with FIGS. 2A and 2B and will not be described in detail again below. Instead, the interested reader is referred to the above corresponding descriptions in connection with FIGS. 2A and 2B.
In this example, the vortex suppression device 402 includes a plurality of protrusions or raised surfaces 404 disposed adjacent the second end 222 of the body 212 and the recessed portion 220. For example, the plurality of protrusions or raised surfaces 404 may be spherically-shaped or round shaped protrusions that extend away from an outer surface 406 of the body 212. The raised surfaces 404 may have any radius and/or radius of curvature (e.g., linear, constant or variable) and may be spaced apart in equal or varying distances about the outer surface 406 of the body 212. The plurality of protrusions or raised surfaces 404 may be formed via machining, casting or any other suitable manufacturing process(es). In other examples, the vortex suppression apparatus 402 may include a plurality of recessed surfaces or openings or any other suitable shape to suppress vortex shedding and, thus, vortex induced vibrations in a fluid flow path (the fluid flow path 208 of FIG. 2A).
Additionally, the example desuperheaters 202, 300 or 400 described herein may be provided as a factory installed option or, alternatively, can retrofit existing fluid systems (e.g., the fluid system 200 of FIG. 2A) in the field.
Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto, but solely defined by appended claims

Claims

A desuperheater (202, 300, 400) comprising a body (212) having a passageway (214) extending between a flange (230) at a first end (216) of the body and at least one opening (218a, 218b) positioned at a recessed portion (220) of the body and adjacent a second end (222) of the body, wherein the body is to be suspended substantially perpendicular to a fluid flow when the desuperheater is coupled to a fluid flow path (208) via the flange such that the at least one opening is substantially parallel to the fluid flow, characterized in that the desuperheater further comprises:
a vortex suppression device (204, 302, 402) integrally formed with the body and disposed along a portion of an outer surface (248) of the body adjacent the second end and the recessed portion and not along a portion of the outer surface of the body adjacent the first end, wherein the vortex suppression device is interrupted by the recessed portion of the body and is suitable for attenuating or suppressing vortex shedding or vortex induced vibrations imparted on the body of the desuperheater by a fluid flowing across the body of the desuperheater.
A desuperheater of claim 1, wherein the passageway is to provide cooling water to the fluid flow path.
A desuperheater of claim 1, wherein vortex suppression device is coupled to the body via welding.
A desuperheater of claim 1, wherein the vortex suppression device comprises a helical straking (246a, 246b, 246c).
A desuperheater of claim 1, wherein the vortex suppression device comprises a plurality of ribs (304).
A desuperheater of claim 1, wherein the vortex suppression device includes a plurality of protruding surfaces (404).
A desuperheater of claim 6, wherein the plurality of protruding surfaces comprise spherically-shaped protrusions.
A desuperheater of claim 1, wherein the body is coupled to a fluid flow pipeline (206) via [a] the flange.
A desuperheater of claim 1, wherein the body includes a non-tapered profile between the flange and the second_end of the body.
A desuperheater of claim 1, wherein the body includes a tapered profile between the flange and the second end of the body.
A desuperheater of claim 4, wherein the helical straking is integrally formed with the body via casting.
A desuperheater of claim 1, wherein a pitch and a height of the helical straking are a predetermined ratio of an outer diameter of the body.
A desuperheater of claim 12, wherein the pitch of the helical straking is between 3.5 and 5.0 times the outer diameter of the body.
A desuperheater of claim 12, wherein the height of the helical straking is 0.1 times the outer diameter of the body.
A desuperheater of claim 1, wherein the fluid comprises superheated steam.